1. Field of the Invention
Aspects of the present invention relate to a nanocomposite, a nanocomposite electrolyte membrane including the same, and a fuel cell including the nanocomposite electrolyte membrane. More particularly, aspects of the present invention relate to a sulfonated polysulfone/metal-carbon nanotube nanocomposite having excellent mechanical properties and ionic conductivity, a nanocomposite electrolyte membrane comprising the nanocomposite, and a fuel cell including the nanocomposite electrolyte membrane.
2. Description of the Related Art
Conventional fuel cells can be classified into polymer electrolyte membrane fuel cells (PEMFCs), phosphoric acid cells, molten carbonate cells, solid oxide cells, and the like. The operating temperature of fuel cells and constituent materials thereof are dependent on the type of electrolyte used in the fuel cells.
The basic structure of a PEMFC may include an anode (fuel electrode), a cathode (oxidizing agent electrode), and a polymer electrolyte membrane interposed between the anode and the cathode. The anode may include a catalyst layer to promote the oxidation of a fuel. The cathode may include a catalyst layer to promote the reduction of an oxidizing agent.
In a PEMFC, the polymer electrolyte membrane acts as an ionic conductor for the migration of protons from the anode to the cathode and also acts as a separator to prevent contact between the anode and the cathode. The polymer electrolyte membrane therefore requires sufficient ionic conductivity electrochemical stability, high mechanical strength and thermal stability at an operating temperature thereof, and thin layers of the polymer electrolyte membrane should be easily formed.
For example, Japanese Patent Laid-open Publication No. hei 9-245818 discloses sulfonated polysulfone as a material used to form a polymer electrolyte membrane. However, the sulfonated polysulfone has poor mechanical properties in a wet-laid state. In addition, a fuel cell using the sulfonated polysulfone has a high probability of methanol crossover, and thus such a fuel cell cannot generate a large amount of power.